staging:rtl8192u: Add spaces around operators - Style

Add the required spaces around '+' and '*' operators. This is a
coding style change to clear the checkpatch issue. There should be
no impact on runtime code execution.

Signed-off-by: John Whitmore <johnfwhitmore@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>